Saw tooth corrugated fastener



y 1936- J. s. M CHESNEY SAW TOOTH CORRUGATED FASTENER Filed Feb. 27, 1953 INVE TOR.

Patented July 7, 1936 PATENT OFFICE SAW TOOTH CORRUGATED FASTENER John Sherman McChesney, Chicago, 111.; Lula A. McChesney, executrix of said John Sherman McChesney, deceased, assignor to Lula A. McChesney, Chicago, Ill.

Application February 27, 1933, Serial No. 658,712 I 11 Claims. (01. -11) This invention relates to toothed fasteners adapted for various uses, but more particularly for fastening abutting pieces of wood.

The invention of this application is an article of manufacture disclosed in my'co-pending applications pertaining to machines and methods of producing fasteners and'particularly corrugated toothed fasteners of the parallel and of the divergently corrugated type. One of these co-pending applications is serially numbered 615,512, Corrugated joint fastener, filed June 6th, 1932; another 682,388, Machine for making and driving corrugated fasteners, filed September 9, 1932; and still another 633,611, Method of making saw toothed fasteners, filed September 17, 1932'. In the application first named the invention disclosed therein pertains to a swagebeveled corrugated fastener, the second application pertains to a machine for -swage-beveling and swage-severing a metallic ribbon into beveled-edged strips thereafter corrugating the strips and severing suitable lengths therefrom; whereas, the third application pertains to a method of producing swaged fasteners. This application is a continuation in part of my application Serial Number 615,512, Corrugated joint fasteners filed June 6, 1932, and the article described in the aforesaid application and the article produced by the aforesaid machine and in accordance with the aforesaid method constitutes the subject matter of this application.

One object of the present invention is to provide a swaged toothed fastener strip that is simple in construction and inexpensive to manufacture. Another object is the provision of a swage-hardened toothed penetrating edge on a fastener strip comprising aseries of teeth having swage-beveled, oppositely inclined, sharpcutting, knife-like edges parallel the relatively wide faces of the strip. A still further object is the provision of a toothed fastener having a swage-beveled, swage-hardened and. swagesharpened penetrating end'produced in its finished form without loss of metal and requiring no further sharpening treatment. Another ob-' ject is the provision of a fastener having a simultaneously swage-hardened, swage-beveled and swage-sharpened toothed penetrating end provided witha succession of oppositely beveled, oppositely inclined, relatively narrow, curved faces in combination with an undulating continuous knife-like cutting edge extending the entire length of the penetrating end of the fastener. 5 Another object is the provision of a fiat fastener having a toothed Penetrating edge in combination with smooth, beveled, hardened, burr-free surfaces.

In the accompanying drawing I have shown one embodiment of the invention, but the construction shown therein is to be understood as illustrative only, and not as defining the limits of the invention. The drawing shows, moreover, the simple method of making the fastener and the fastener is shown on an enlarged scale for clearness.

In the accompanying drawing:

Figure 1 is a side elevation of the toothed corrugated fastener. n V, V V

Fig. 2 is a plan view looking at the toothed edge of Fig. l illustrative of the undulating wave-like formation of the knife-like cutting edge positioned within the contour of the relatively wide corrugated side surfaces of the fastener, and of the tooth points in misaligned arrangement with respect to the plane of the medial line XX of the fastener, i. e., that line midway the crests of the corrugations;

Fig. 3 is a side elevation, illustrative of the progressive steps in the swagebeveling and swage-severing treatment of a fiat metallic rib bon to form toothed strips, the untreated portion of the ribbon merging into the initially treated portion and thereafter into the interspaced opposingly formed pre-sharpened. and scored-to-length, uncorrugated finished fastener blanks in connected, scored, flat ribbon formation.

Fig. 4 is an end cross section on line 4-4 of Fig. 2 on the medial line of the fastener and substantially at right angles to the side edges of the corrugations and illustrative of the substantially equally beveled, penetrating end of V shaped appearance in end cross section.

Fig. 5 is an end cross section taken on line 5-5 of Fig. 2 on the crest of the corrugation and substantially at right angles to the side edges thereof and is illustrative of the unequally beveled penetrating end of V shaped appearance in end cross section.

Fig. 6 is a greatly enlarged view looking at the toothed edge of Fig. 3.

Fig. 7 is a greatly enlarged plan view looking at a section of a characteristic saw tooth edge of Fig. 3 and. Fig. 6fafter bending and rebending to produce corrugations.

Fig. 8 is a view in perspective of one of a set of co-acting swaging and scoring dies adapted to the manufacture of the fastener.

Fig. 9 is a perspective view illustrative of a finished toothed edged flat strip scored for of the corrugations to produce a: toothed pene- I trating end, as hereinafter described; or may first require the corrugation of a flat Inetalstrip, l- 7 1 strip toproduce toothed formations on the penecorrugated toothed fastener.

In the prior art as far as is known to me, all toothed corrugated fasteners havinga sharpened beveled penetrating end, are made by methods employing the removal of metal and requiring numerous machine operations. In the making of prior art fasteners the first operation may consist of imparting a straight, bevy eled, cutting edge to a' fiat metal strip, and

g|2 are concurrently impressed by the co-acting scoringel'ements I and 5 preferably arranged to thereafter corrugating and. removing. portions thereafter beveling one end of thecorrugated tratingend, either method requiring a series of slow, tedious and expensive-operations usually comprising a process of grinding, milling, angularlyshearing or'rotary disk shearing thereby removing a' relatively large part of the metal-of the corrugations and producing a series of reversed beveled surfaces of crescent shaped ap-r .pearance when viewed in side elevation. pointed penetrating end members character-c isticof these fasteners arepositioned uniformly The on, or centrally on, or spaced centrally diagonal ,the plane; of the medial line' of the fastener.

The grinding methodis objectionable. in that the metal is heated to such an'extent that the temper is drawn, thereby softening the penetrating end :and developing an over-hanging fin on the ground surface. The fins and sofltened metal impede downward progress causing the fastener to hunt and'to tear the fibre during" the penetration of the material: into which the fastener is driven.

When milling and shearing methods are emf; ployed, the points of the teeth are, or should be, formed in the plane of the medial lineof the fastener, and this treatment results in'the.

formation of rough edges on the toothed edge and occasionally the points of the teeth are deflected to one side or. the other of .the medial line of the fastener, thereby requiring a further operation to'reposition. the strayed teeth and a d'eburring operation to'remove fins and roughedupmet'al of the toothed edge; the teeth are further processed by g inding to "impart a desirably 'keen edge to the extreme points,

Outstanding features of novelty of mypres 'ent invention are: swage-hardened, burnished;

oppositely inclined; beveled; burr-free surfaces intersecting intermediate the longitudinal side edges at the penetrating end, forming cutting edges and tooth apexesl In'making my fastener, I employ a length of metallic ribbon l, of the required width, gauge and tempen-and having relatively wide parallel faces 2 and. 2a. The ribbon is; advanced in 'the direction of its .lengthin guided: position ,tvith relation to opposed co-acting tooth-swaging .elements-3, and-scoring elements 4 and Sand combined stock guidingIand contacting lands 1,

all mounted in suitable element holder 6, said elements adapted to opposingly co-act in register with like elements. Operating means cause said co-acting elements to forcibly. approach each other in register to. within a 'pre-determined disy tanceshort of contact by'combined ribbon guiding and opposed contactinglands I; Fromtime of contacting of the elements 3, 4 and 5 with the side surfaces. 2,and 2a of the fiat strip I, to the seating of the'contacting lands 1., the

metal :of the strip at the penetrating end I0 is opposingly compressed by the 'swaging elefastener 28 from the next 2,046,338 a g, V

ments functioning to opposingly impress their reverse formation into the relatively wide longi- I tudinal surfaces 2 andZa of the strip and inter-. mediate the side edges thereof in the general direction of its length, therebyto simultaneously form well-defined oppositely beveled, oppositely inclined teeth 9 on the penetrating end H] of each opposinglyswage-formed, separated, bev--,

eled, sharpened, fiat fastener strip Hand Ila. At pie-determined intervals transverse scorings score at the tooth roots 20. The finished scoredtrating end It) and to disengage "the finished succeeding fastener blank l3 at the scoring I 2. I,

The tooth 9; is bounded by four work-hardened surfaces formed by oppositely inclined, op-' positelyswage-beveled planes of surfaces I 4 and I5 on the one side pf the mid-line YY of the flat strip and by similar surfaces l6 and I! as illustrated in Fig.6.. 7 a

During the corrugating of the strips the apexesof the teeth are positioned in misalign'ed relation with respect to the mid-line of the fastener and the cutting edges of the teeth as sume a wave-like formation within the confines of the side edges of the corrugationsand short of the outer edges at the crests of thecorrugations. In the finishedcorrugated fastener the pyramidal work-hardened apex of each tooth is bounded by four oppositely beveled, oppositely inclined, intersecting, curved surfaces, forming four curved, oppositely inclined edges originating atthe apex, i. e., two relatively'short edges extending oppositely from the apex" and tore V minating, on the longitudinal side edges of the corrugations at substantiallyright angles there-- to, and tworelatively long, curved, sharp-cutting, oppositely inclined edges extending from the apex and between the, longitudinal side edges of the corrugations and terminating at the tooth root, joined and continuing in like manner on each succeeding tooth, thus forming a continuous wave-like cutting edge on the'workhardened penetrating end of the fastenerl The continuous swage-hardened knife-like cutting edge is of wavy appearance and lies entirely within the longitudinal side edges. The four opposed planes of' the beveled surfaces l4- l5 and 16+ intersect to form a'pyramidalapex l8 intermediate the side surfaces 2:and 2a and thepalredplanes'of' surfaces H, H) and l5, l1 forma knife-like, sharp hardened, continuous cutting edge l:9a extending'uninterruptedly from tooth root 20,-to a'pexlB, to the next tooth root 20, and in like manner 3 connect successively thereafter on each tooth of the penetrating end of the fastener.- The tooth of:

smooth burr-free work-hardened burnished sur-' facesofthe bevels ll, I5 and l6, l1 and the.

metal included therebetweenis of greater hardness and density than the adjacent metal of the strip; These features of'novelty are character- 7 istic of the burr-freepenetrating end of this and of the fasteners disclosed inthe above mentioned co-pendingapplications. 1 n a r p The increased density of the metal ;of the fastener imparts to the apexes and the cutting edges formed by the intersections of the planes,

increased strength, whereby they'become better adapted to resist deformation, to maintain their sharp knifelike cutting edges, and to drive easily and cleanly into the material tobe joined either with or across the grain, than fasteners of the prior. art. I'find' it desirable to score the fastener strip at pre-determined intervals insuch manner as to produce full teeth and'thescorings l2 are preferably so positioned as to extend transverse the faces 2. and 2a to the tooth root 20. The severed sections or blanks l3 shown in Fig. 3, thus provide fiat fasteners having swage hardened, swage-severed and swage-sharpened teeth 9 which fiat fasteners are useful for certain purposes. The corrugated fastener is completed when the fiat blanks l3 are bent and rebent inthe forming of corrugations 2|. Any suitable -machinery may be employed for corrugating and for this purpose and to produce fasteners of the parallel, or of the divergent type, I find mated corrugating rolls 22 and 22a mounted'onshafts 23 and 23a respectively to be well adapted for the work of corrugating, for positioning the teeth apexes in pre-determined relation with respect to the medial line X-X of the corrugated fastener, and for separating the finished fastener at the scored lines I2.

The surfaces l4, I5 and 16,11 of the uncorrugated strip become the curved beveled surfaces 24, 25, 26, 21 respectively of the corrugated strip. As illustrated in Fig. 5 and Fig. '7 the beveled surfaces 24, 25 intersecting with the beveled surfaces 26, 21 form the curved continuous cutting edge IQ, of sinous or of wavelike-formation which remains inplan view with in the contour of the side surfaces of the fastener and approaches and 'lies substantially upon the crest of the corrugations 2| at the outer edge thereof, i. e., that crest edge farthest away from the medial line X-X of the corrugated fastener.

The cutting edge I 9 retains its sinuous or wave-like formation as shown in Fig. 1 and Fig. 7 with respect to the corrugations and thruout the length of the corrugations of the fastener, independent the position of, or arrangement of, the number of teeth, or the spacing of the teeth. In Fig. 5 the cutting edge 19 is on the outer crests of the corrugations and coincides with the apex l8 of the tooth formation. Reference being had to Fig. 2, the cutting edge IQ of Fig. 5 retains the Same relative position on each of the outer crests of the fastener irrespective of the changing position of the succeeding apexes l8 and. the root 20 thereof, and in like manner the cutting edge l9 crosses the mid-line XX of the corrugations -of the fastener substantially on the mid-line of the strip YY as shown in end cross section in Fig. 4.

The beveled curved surfaces 24 and 25 adjacent the outer edge of the crests of the corrugations are of less included angle than the opposed curved surfaces 26 and 21 which face the mid-line X-X, as in Fig. '7. From this novel arrangement of the beveled teeth and unsymmetrical or random apexes, it is obvious that, during the driving operation, the material intermediate the inner crests of the corrugations is acted upon approximately thru an arc of 180 degrees, is crowded, compressed and confined between the inclined surfaces 26 and 21 of the inner crests of the corrugations, whereas, the oppositely positioned, curved beveled surfaces of the outer crests of the corrugations are substantially parallel to the surface 2 of the corfastener may be driven without self-clinching mi and in a straight line of penetration. My fastener isvbetter adapted toibe driven into material of.narrower width, than fasteners of the prior art, due to the novel tooth configuration and staggered arrangement .of the apexes and 15 to the relatively small included angle of the curved surfaces on the outer edge of the crests of'the corrugations.

The property of self-clinching may be imparted to the tooth 9 by a change in tooth form 20.

or by changing the length of the tooth between the apex? and the root 20, or by increasing or decreasing the temper of the metal. The above, in combination with the greater included angle'of'the bevels of the inner crests of the 25.

corrugations, exerts on the tooth apex IS a lateral force sufficient to cause the tooth to travel outwardly, traverse the direction of penetration of the corrugations.

, Manifestly, the construction shown is capable 30:

of a wide range of modifications, for example, the distance between theroot 20 and the'apex I8 may be of any desired depth; the distance between the roots 2!! of each tooth may be of any desired width. Both the depth and the 35.

width of the tooth mayv be varied within each fastener blank; more particularly to'form 'the wide central tooth of the divergent fastener, thus producing a variety of tooth formations on the same blank. In the prior art, the num- 40 her of corrugations bears a direct numerical ratio of one corrugation to two apexes when the teeth are formed after corrugating. The substitution of modified tooth form I do not consider a departure from my construction and such modification as is within the scope of my claims, I consider within the spirit of my in vention.

I claim:

1. A fastener comprising a swage-bevelled swage-sharpened toothed edged strip swagesevered from metallic ribbon, corrugations extending traverse said toothed edge, said toothed strip having curved bevelled side surfaces on the penetrating end thereof, said teeth having apices positioned in misaligned relation with respect to the medial line of the corrugations, said toothed strip having two apices on each corrugation.

2. A fastener comprising a length of corrugated metal having a series of teeth, each of said teeth beingdefined by beveled side surfaces which are curved and extend oblique the medial plane of the fastener.

3. A fastener comprising a length of corrugated metal having a series of teeth, each of said teeth being defined by beveled side surfaces which are curved and extend oblique the medial plane of the fastener, the outer edges of said beveled surfaces forming an undulating continuous cutting edge when the fastener is viewed in elevation from its entering end.

4. A fastener comprising a length of corrugated metal having an entering edge consisting of a series of teeth, the opposed side surfaces of which are beveled, the outer edges of said side surfaces forming, undulating :continuous cutting edge whenthe-fastener is viewed el'e vationfrom its entering end. 7

'5. A xfastener comprising a length of corru- V gated metal having-an entering edge consisting of a'series of teeth, the opposed side surfaces of V which are beveled and swage-hardened, the

outer edges of said -beveled and swagehardened side surfaces Vforming an undulating continuous sides thereof, saidcutting edge intermediate the swage-hardened cutting edge when the fastener is viewed in elevation from its entering end.

6. A fastener comprising a length of cormgated metal'having a series of s'waged'hardened teeth on one edgerthereof, thehardened surfaces of the metal of the opposite sides of. said teeth 7 being curved and oppositely beveled; the outer edges of said oppositely beveled surfaces forming anundulating cutting edge when thexfastener is viewed in elevation from its entering end. "73A fastener: comprising aleng'th er corrugated metal stock having a'series'of swagehardened teethon one edge thereof, the, hardened surfaces of the metal of the opposite sides of each of said teeth 'being curved and oppositely beveled, the'outer edges of said swagebeveled surfaces-forming a cutting edge when the fastener is viewed in elevation" from its entering end,- said cutting edge lying entirely within the contour of the corrugations and. short of the outer crests of the corrugations on the convex crests of the corrugations lying substantially midway the 'side faces of the metal stock.

8. A fastener comprising a length. of corrugated metal having a series 01' swage-hardened teeth on one edge thereof; the hardened surfaces of the metal of the opposite sides of each of said teeth beingcurved and oppositely beveled; the outer'edges of said oppositely beveled surfaces "forming an undulating cuttingedge when; the

fastener is fviewed in elevation from its entering end,the oppositely beveled opposite-side sm'races s presenting four beveled'iaces' defining a idal apex for each tooth. V

9.;A- fastener comprising a length of coring gated metal having an entering1edge consisting of a series or'teeth, 'opposed'side surtlcsof 1a: 7

series of teeth lying in unsymmetricaiarrange ll with respect to the length of the Strip, said'ml fastener being provided. on its'enterin'giend Iifl-r a series of swage hardened teeth, the 3 surfaces of the metal of. the-opposite sides'ot each of saidteeth being curved and beveled and the ratio of 'said'teeth to each 01' saidielatively 253 small corrugationsbeing greater than two to one.

,11. A'fastener device comprising a length of metal stock provided with a swaged serrated beveled cutting" edge, saidmetal being corru gated transversely oi the serrated cutting edge 80" forming a'series of-curved teeth having curved 'beveled side edges, said series of teeth being f positioned by the corrugations to presenta group of apexes alternately disposed with respect to a next adjacent group on opposite sides of 85 the longitudinal mid plane of the fastener.

JOHN 

